Renamed QuickCheck to Test everywhere, since QuickCheck isn’t even used in the automated testing module.

- Added correct handling of LIsnull in QuickCheck.
- Fixed a bug in Rewrite.hs that wasn’t causing issues yet, but was a bug nonetheless.
- Sped up QuickCheck tests by making the number of iterations dependent on the specific test.

  - Fixed bug that caused some QuickCheck tests to throw an exception because not a complete substitution was taking place.
  - Uncommented the legendary 16th bug that causes an endless loop when Z3 is used. It doesn’t cause an endless loop with QuickCheck, but QuickCheck does give the wrong answer :’(.

All in all, the very naive testing module correctly tests 13/16 tests at the moment (most of the time at least; it’s random).

- Removed the eval tests.
- Added tests for QuickCheck
- Note that something is broken: multiple tests fail.

* LogicIR EDSL.
* Minimized LogicIR.
* General styling fixes.
* Supressed output in tests.
* Single-threaded test execution.